Common behavioral problems in patients with Alzheimer's disease (AD) include agitation, verbal and physical aggression, sleep disruption, incontinence, wandering, repetitive actions, screaming, and inappropriate sexual behavior. These behaviors contribute to a diminished quality of life for patients and caregivers, since they often require chemical or physical restraints, accelerate the need for institutionalization, increase the physical and emotional strains upon family members, and increase health care utilization and costs. Nighttime sleep disruption and daytime agitation are among the most common and troubling of these behaviors for AD patients who live with a caregiver in the community. Several lines of research suggest that AD patients in both nursing homes and in the community are exposed to far less ambient light than age-matched controls, that sleep fragmentation is common in AD and that sleep disruption contributes to both nighttime wakening/wandering and daytime agitation. Exposure to bright light during the day has been shown to entrain human sleep/wake cycles, enhance nighttime sleep efficiency and elevate affect, and there is preliminary evidence to suggest that bright light exposure can reduce nighttime awakenings and even improve daytime behavior in patients with AD. Music listening has also been reported to acutely calm AD patients with agitation and the characteristics of this effect have never been studied in a controlled manner. The goal of this project is to determine whether bright light exposure or music listening can decrease nighttime awakenings or daytime agitation. This project will randomize community-dwelling AD patients with behavioral problems into one of three groups. One group will receive 1 hour of bright light exposure daily for 10 days, the second group will receive 1 hour of a music listening experience daily for 10 days. The third group will spend the same amount of time in the same testing room under identical circumstances, except that they will have no specific intervention. Primary outcome variables will include sleep quality as measured by wrist-mounted light/activity monitors and caregiver responses on validated scales of observed behaviors. Caregivers and scale administrators will be blinded to the experimental condition. If either or both of these non-pharmacological interventions prove effective in mediating some of the disruptive behaviors associated with AD in this preliminary study, then a subsequent large-scale trial could determine the optimal "dosing" parameters and conditions. Should this project support the efficacy of these interventions, addition of these simple and inexpensive treatment modalities to homes and daycare centers could offer relief from disruptive behaviors that will significantly enhance the quality of life for victims of Alzheimer's disease and their families.